In recent years, as an environmentally-friendly vehicle, a vehicle that has a power storage device (e.g., a secondary battery, a capacitor or the like) mounted thereon and travels using the driving power generated from the power stored in the power storage device has received attention. Such a vehicle includes, for example, an electric vehicle, a hybrid vehicle, a fuel cell vehicle and the like.
In these vehicles, it has been demanded to improve energy efficiency by reducing fuel consumption and electric power consumption for the purpose of further reducing environmental load.
Japanese National Patent Publication No. 2008-520485 (PTL 1) discloses a hybrid vehicle including an internal combustion engine and a motor generator, wherein the motor generator is controlled to alternately repeat a first interval during which the motor generator is driven to operate with a high output larger than the actual electric power consumption of a vehicle electric system and a second interval during which the motor generator is switched off, when the motor generator is in a generator mode.
According to Japanese National Patent Publication No. 2008-520485 (PTL 1), when the motor generator operates as a generator, the motor generator is driven at an operating point of high efficiency in the first interval and the motor generator is stopped in the second interval. With this, continuation of inefficient operation of the motor generator during power generation operation is suppressed, and thus, the energy efficiency of the vehicle in the power generation operation can be improved.
In addition, Japanese Patent Laying-Open No. 2010-6309 (PTL 2) discloses a hybrid vehicle including an internal combustion engine and a motor generator, wherein traveling using the driving power generated by the internal combustion engine and traveling in an inertial state in which the internal combustion engine is stopped are alternately repeated. With this, the internal combustion engine can be driven at an operating point of high efficiency, and thus, the fuel consumption can be improved.